1. Technical Field
Safe and effective vaccines to prevent group A streptococcal (GAS) infections are needed. A multivalent vaccine is described herein that induces an immune response against multiple GAS serotypes and that may be useful for immunizing subjects in need thereof.
2. Description of the Related Art
Efforts to develop safe and effective vaccines to prevent group A streptococcal (GAS) infections have been ongoing for decades. Although a number of GAS antigens have been identified as potential vaccine components (see, e.g., Steer et al., Curr. Opin. Infect. Dis. 22:544-52 (2009)), the lead candidates are the type-specific peptides representing the amino-terminal regions of the surface M proteins (see, e.g., Kotloff et al., JAMA 292:709-15 (2004); McNeil et al., Clin. Infect. Dis. 41:1114-22 (2005)).
The major burden of disease in North America, Europe, and other economically developed regions and countries is uncomplicated pharyngitis and serious, invasive infections (see, e.g., Carapetis et al., The Lancet Infectious Diseases 5:685-94 (2005)). The global burden of GAS infections is most significant in poor countries where acute rheumatic fever (ARF) and rheumatic heart disease (RHD) are rampant (see, e.g., Carapetis et al., supra). Vaccine prevention of the infections that trigger ARF using M protein-based vaccines has been considered a challenge because the GAS emm types present in developing countries differ compared to economically developed areas of the world (see, e.g., Steer et al., The Lancet Infectious Diseases 9:611-16 (2009)). Immunogenicity of a 26-valent M protein-based vaccine in pre-clinical (see, e.g., Hu et al., supra) and clinical studies (see, e.g., McNeil et al., supra) has been reported. However, the 26-valent vaccine does not provide protection against infection by a sufficient number of different GAS serotypes for optimum benefit and use in both developing and developed countries. Accordingly, a need exists for development of improved therapeutics and vaccines, which can be economically produced, for treating and preventing GAS infections.